Refactoring of PsGet.psm1 with the goals:
- unification of code style
- matching style recommondations for PowerShell (eg function names following the approved verb convention also internally)
- reduction of duplicate code (e.g. DownloadModuleFromWeb and DumbDownloadModuleFromWeb)
- less implicit dependencies between the miscellaneous functions considering error checking and handling
- documentation of expectations on function users
- removing all cases where errors did not cleanup afterwards leaving temp-files

Change in functionality:
- preserve the default PSModulePath if the environment variable is not defined for user or machine on persisting

For code style is more or less:

* Language keywords lowercased
* Function and variable cased like defined
* Function parameters begin with a uppercase
* Local variables with a lowercase
* Braces are placed like in C#
* SYNOPSIS of a function is places at top
	* Function top is easier to find as the end for reference
* Double quoted string are only used if format is necessary to signal that the string use format

Considered Links:
[http://ramblingcookiemonster.wordpress.com/2013/12/08/building-powershell-functions-best-practices/]
[http://msdn.microsoft.com/en-us/library/ff926074.aspx]
[http://windowsitpro.com/blog/my-12-powershell-best-practices]
[http://stackoverflow.com/questions/2025989/what-is-the-recommended-coding-style-for-powershell]
[http://blog.octo.com/en/powershell-v2-my-best-practices/]
Refactor the tests to a more consistent code style and improved the isolation of the tests. No temp files or environment variable changes remain after test execution anymore.
Merge pull request #135 from flofreud/cleanup-refactoring

Cleanup refactoring